In modern medical examination facilities for recording fluoroscopy images, such as are described for instance from the information in the article “AXIOM Artis dBA/AXIOM Artis dBA DynaCT/Biplane C-arm System with Flat Detector for Angiography” by Siemens Medical Solutions Order No. A91001-M1400-G940-2-7600, publication AX CRM NA 04053, it is not only possible to record two-dimensional fluoroscopy images, but also to obtain three-dimensional image datasets by rotating a C-arm about the patient for instance. In such cases soft parts are typically recorded three-dimensionally and displayed. Three-dimensional angiographs can however also be produced by subtracting contrast agent recordings and native recordings.
The size of the recording area, in other words the radiated region, is determined by the size of the radiation cone, in practice thus by the size of the radiation detector.
For some applications, above all in the abdominal region, but also on limbs such as the legs for instance, larger target volumes, particularly in the longitudinal direction of the patient, the z-direction, must also frequently be covered. To this end, it was proposed to implement two rotations of the C-arm for instance in a consecutive fashion, and to move the patient support by a suitable amount between these recordings. Subsequently three-dimensional reconstruction image datasets are created from each of the two volumes recorded, but the tedious process of registering the images with one another is generally required here in order to allow a joint display. This method proves to be particularly disadvantageous if subtraction images are to be recorded by administering a contrast agent. In this context, it is namely necessary in this instance to administer the contrast agent twice, which may lead to an additional strain being imposed on the patient both in terms of time and also physically.